This article is about the air purifier. For the psychiatric treatment, see Negative air ionization therapy. This photo shows the sterilisation effects of negative air ionization on a chamber aerosolised with Salmonella enteritidis. The left sample is untreated; Photo taken in a lab operated by the United States Department of Agriculture. An air ioniser (or negative ion generator or "Chizhevsky's chandelier") is a device that uses high voltage to ionise (electrically charge) air molecules. Negative ions, or anions, are particles with one or more extra electrons, conferring a net negative charge to the particle. Cations are positive ions missing one or more electrons, resulting in a net positive charge. Most commercial air purifiers are designed to generate negative ions. Another type of air ioniser is the electrostatic discharge (ESD) ioniser (balanced ion generator) used to neutralise static charge. In 2002, Cecil Alfred 'Coppy' Laws was credited with being the inventor of the domestic air ioniser in an obituary in The Independent newspaper.

Air ionisers have been used to eliminate the occurrence of air-borne bacterial infections and to reduce static electricity buildup in electronics. Air ioniser and purifier with its dust collection plates removed Air ionisers are used in air purifiers to remove particles from air. Airborne particles are attracted to the electrode in an effect similar to static electricity. These ions are de-ionised by seeking earthed conductors, such as walls and ceilings.To increase the efficiency of this process, some commercial products provide such surfaces within the device. The frequency of nosocomial infections in British hospitals prompted the National Health Service (NHS) to research the effectiveness of anions for air purification, finding that repeated airborne acinetobacter infections in a ward were eliminated by the installation of a negative air ioniser—the infection rate fell to zero, an unexpected result. Positive and negative ions produced by air conditioning systems have also been found by a manufacturer to inactivate viruses including influenza.

The SARS epidemic fueled the desire for personal ionisers in East Asia, including Japan (where many products have been specialised to contain negative ion generators, including toothbrushes, refrigerators, air conditioners, air cleaners, and washing machines). There are no specific standards for these devices. Ionisers are distinct from ozone generators, although both devices operate in a similar way. Ionisers use electrostatically charged plates to produce positively or negatively charged gas ions (for instance N2− or O2−) that particulate matter sticks to in an effect similar to static electricity. Even the best ionisers will also produce a small amount of ozone—triatomic oxygen, O3—which is unwanted. Ozone generators are optimised to attract an extra oxygen ion to an O2 molecule, using either a corona discharge tube or UV light. At concentrations that do not exceed public health standards, ozone has been found to have little potential to remove indoor air contaminants.

[3] At high concentrations ozone can be toxic to air-borne bacteria, and may destroy or kill these sometimes infectious organisms. However, the required concentrations are sufficiently toxic to humans and animals that the US FDA declares that ozone has no place in medical treatment[4] and has taken action against businesses that violate this regulation by offering therapeutic ozone generators or ozone therapy.whirlpool whispure 510 air purifier price[5] Ozone is a highly toxic and extremely reactive gas.honeywell hepaclean whisper quiet air purifier with uv light[6] A higher daily average than 0.1 ppm (100 ppb, 0.2 mg/m³) is not recommended and can damage the lungs and olfactory bulb cells directly.brookstone air purifier ozone

A number of studies have been carried out on negative ion generators. Some studies show that the ozone generated can exceed guidelines in small, non ventilated areas.[7] One study showed that ozone can react with other constituents to increase pollutants such as formaldehyde. Consumer Reports, a non-profit US-based product-testing magazine, reported in October 2003 that air ionisers do not perform to high enough standards compared to conventional HEPA filters. The exception was a combination unit that used a fan to move air while ionizing it. In response to this report, The Sharper Image, a manufacturer of air ionisers (among other products), sued Consumer's Union (the publishers of Consumer Reports) for product defamation. Consumer Reports gave the Ionic Breeze and other popular units a "fail" because they have a low Clean Air Delivery Rate (CADR). CADR measures the amount of filtered air circulated during a short period of time, and was originally designed to rate media-based air cleaners.

The Sharper Image claimed that this test was a poor way to rate the Ionic Breeze, since it does not take into account other features, such as 24-hour-a-day continuous cleaning, ease of maintenance, and silent operation. The United States District Court for the Northern District of California dismissed the case, reasoning that The Sharper Image had failed to demonstrate that it could prove any of the statements made by Consumer Reports were false. The Court's final ruling in May 2005 ordered The Sharper Image to pay US $525,000 for Consumer Union's legal expenses. Air ionisers are sometimes used in places where work is done involving static-electricity-sensitive electronic components, to eliminate the buildup of static charges on non-conductors. Grounding with ground straps or other methods eliminates static buildup on conductors, but not non-conductors. If you have asthma symptoms, an air filter or room air cleaner may help you to breathe better. The same is true for those with hay fever (allergic rhinosinusitis) or COPD (emphysema or chronic bronchitis).

If you live with a smoker, an air filter or room air cleaner is likely to be helpful. Almost all room air cleaners efficiently remove smoke from the room (as long as the air filter is large enough, the fan turned on, and the air filter is maintained). Recommended Related to Asthma A bronchodilator is used by almost all people with asthma as a way to open the airway passages. Short-acting bronchodilators are used as a "quick relief" or "rescue" medication, while long-acting bronchodilators can be used every day to control asthma -- in conjunction with an inhaled steroid. Read the Bronchodilators and Asthma article > > Can air filters help prevent asthma symptoms? Room air cleaners remove small particles that are in the air near the air cleaner. However, room air cleaners don't remove small allergen particles that are caused by local disturbances, such as the microscopic house dust mite feces that surround a pillow when your head hits it (or you turn over in bed).

You inhale these allergens before they ever get near the room air cleaner. Room air cleaners take 5 to 15 minutes to remove such temporary local sources of dust and allergens. Wall-to-wall carpets also provide a massive source of allergens, which simply cannot be removed by vacuuming or the use of a room air cleaner. However, these accumulated allergens remain in the carpet until disturbed. Vacuuming carpets, which uses a beater brush, causes very large amounts of allergens to be thrown into the room, even if a HEPA vacuum cleaner is used. Room air cleaners are also unlikely to be adequately effective if the source of the allergens remains in the home, such as a cat, dog, bird, or hamster. Room air cleaners only work for the room in which they are placed. Since you spend eight hours in your bedroom every night, this should be the first room in which to locate a room air cleaner. However, you may also spend several hours each day in your kitchen, TV room or office, so you may need a separate room air cleaner for each of these rooms.